Automatic control apparatus for driving cooling fan of automobile engine



Aug. 16, 966 KOZO MASUURA 3,266,471

AUTOMATIC CONTROL APPARATUS FOR DRIVING COOLING FAN OF AUTOMOBILEENGINE" Filed Sept. 25. 1965 2 Sheets-Sheet 1 IN VENTOR.

K Mh uuka BY 9111 63 m g- 1966 KOZO MASUURA 3,266,471

AUTOMATIC CONTROL APPARATUS FOR DRIVING COOLING 'FAN OF AUTOMOBILEENGINE Filed Sept. 25. 1963 2 Sheets-Sheet 2 k Mnmqm INVENTOR.

United States Patent 3,266,471 AUTGMATIC CONTROL APPARATUS FOR DRIV- INGCOOLING FAN OF AUTOMOBILE ENGINE Kozo Masuura, 58 Yawata Shimizu-mura,Sunto-gun, Shizuoka Prefecture, Japan Filed Sept. 25, 1-963, Ser. No.311,498 1 Claim. (Cl. 12341.12)

This invention is concerned with providing a clutch mechanism forturning a fan, wherein a hollow tubular cavity 2 provided within a rotorshaft 1 of a Water pump along the axis of said shaft is divided into twoparts, namely, a working shaft cavity 4 and a thermosensitive cavity 5by means of reciprocating members 3 adapted for reciprocating in thedirection of said axis, a thermo-sensitive chamber 7 is defined throughcontact of the circumferential wall of said thermo-sensitive cavity 5with circulating water, said chamber being filled with a material 8which is adaptable for changing the internal pressure therein accordingto temperature variations in said chamber, a spring is provided forreciprocating the working shaft 9 resiliently against the change in the'internal pressure, and said clutch mechanism for turning a fan isconnected With the working shaft 9.

In the case that the material 8 to be filled in the thermosensitivechamber 7 provided in the apparatus of this invention is a liquid whichis adaptable for changing the internal pressure through its evaporationand condensation, the quantity of the material should be such that bothvapor and liquid phases can be kept at least until a predeterminedpressure (a predetermined temperature) is reached, while use of such amaterial as wax, which can hardly be vaporized, makes it necessary toprovide the working shaft 9 with the reciprocating movement ofreciprocating members 3 through the spring 10'. For setting the Workingtemperature of the fan, the starting pressure of the working shaft 9 isrestrained by restraining means 11, 11, 11" and 11" provided within thehollow tubular cavity formed in the rotor shaft and, when apredetermined pressure (a predetermined temperature) is reached, therestraint is removed so that the working shaft 9 is moved forwardthereby the clutch is engaged. In turn, in order that the clutch will beauto: matically disengaged when the temperature of cooling water goesdown to a predetermined value, means is adopted for regulating eitherthe slope of a conical inner surface 13' adapted to be pressed by aclutch presscontacting surface 12 or the resiliency of the spring 10 orthe both.

The characteristic features and advantages of this invention will beunderstood from the following description made with reference to theaccompanying drawings, in which:

FIG. 1 is a longitudinal sectional view of an embodiment of thisinvention;

FIG. 2 is a sectional view taken along line II of FIG. 1;

FIG. 3 is a side view taken in section of the resilient member 20 in theportion indicated by A;

FIG. 4 is a longitudinal sectional view of another embodiment of thisinvention; and

FIG. 5 is a perspective view of a different form of a resilient member.

In the drawings, the like numerals indicate the like parts or theequivalents.

Referring to FIG. 1, a working shaft is restrained by means ofrestraining means provided within aworking shaft cavity 4, accordingly,a fan clutch is disengaged. 1 is a rotor shaft, 6 is the tube wall of athermo-sensitive cavity 5, 8 is a material which is vaporized orcondensed through change in its vapor tension according to the vari-3,266,471 Patented August 1 6, 196.6

ations of Water temperature that may be sensed through the tube wall 6,3 is reciprocating members adapted to divide the cavity 2 formed withinthe rotor shaft into the thermo-sensitive cavity 5 and the working-shaftcavity 4 respectively, 7 is a thermo-sensitive chamber confined by thereciprocating members 3, inner surface 14 of the cavity, and the tubewall 6 of the side cavity 5. The

reciprocating members 3 are provided by brazing at 15' the edges ofbellows to the boundary of the cavities 4 and 5. 16 is a projectionforming the head portion of the reciprocating members 3, 9 is a workingshaft, 10 is a spring for engaging the end of the shaft 9, 1" is acommunicating aperture adapted for communication between the inner andouter portions of the hollow shaft, 17 is a resilient clutch fixed tothe working shaft 9, which resilient clutch is adapted to reciprocate ina communicating aperture 1", 12 is a clutch mounted to an arm end, 12 isa clutch press-contacting surface, 13 is a truncated cone-shaped fanboss made of synthetic resin, 13' is an iron plate embedded in theconical inner side surface of the boss, 13 is an iron plate embedded inthe vertical outer side surface of the boss, 18 is an annular platesecured to the shaft end, 18' is a clutch press-contacting surface, 19is an engaging portion of the fan boss, 1 is a retainer for preventingthe engaging portion 19 from sliding laterally, 20 is a resilient memberconsisting of a solid butterfly spring as shown in FIGS. 2 and 3, or aresilient member consisting of wave-shaped annular spring shown in FIG.5, 21 is a pump housing, 23 is a pump rotor, 24 is a Water intake portof the pump, 25 is a water exhausting port, 26 is a cover, 27 is ballbearings and 22 is an arm for transmitting the rotation of a pulley 22to the rotor shaft.

FIG. 4 shows another embodiment of this invention in Which wax isemployed; but the structure and operations thereof are similar to thoseillustrated in FIG. 1 except for reciprocating member and partassociated therewith, therefore, description of the structure andoperations are eliminated. In fact, a combination of a reciprocatingmember 3 (rubber plate), soft rubber 3, projection 16 and spring 10'serves to provide the same function as in the case of the reciprocatingmembers. I

In accordance with this invention, the structure can be greatlysimplified, the manufacture can be facilitated, and

pump without using a conventional rotor. Also, the state.

in which the clutch is half-engaged can be avoided, since the forwardmovement of the working shaft due to the change in the internal pressureof the thermo-sensitive chamber is restrained by the restraining meansuntil the predetermined pressure (predetermined temperature) is reached,thus regulating the time when the cltuch is to be engaged.

On the other hand, the. time for the clutch to be disengaged will be setby the decrease in the internal pressure of the thermo-sensitive chamberand by the action of the spring 10 through pre-adjustment of the slopeof the press-contacting surface and the resiliently pressed state whichoccurs in the slanting inner surface of the fan boss by the clutchsurface when the clutch is engaged.

Since the resilient member has resiliency, it regulates the positionwhere the fan boss is out of contact with 3,2eaa71 the clutch surface18', thereby smoothing the separation of the clutch on the boss outersurface 13''. v The major part of the fan is made of synthetic resin,and thus its entire weight becomes smaller, accordingly, itsrevolutionary momentum becomes smaller as compared with the conventionalfans made of metal. Furthermore, in order to improve the friction in theclutch press-contacting surface, embedding iron plates in the inner andouter, side surfaces 13 and 13" of the boss made of synthetic resin maycause the revolutionary torque of the fan to be smooth. A substantiallygreat pressing force is required in order to rotate the fan by means ofpresscontact of the clutch, however, satisfactory results could not beobtained simply by means of cubical expansion of the material accordingto variations in the temperature of cooling water. Either only expansiveforce of gas or cubical expansion of a material such as wax has beenemployed heretofore, however, power resulting from the former isinsufficient and the latter is short of resiliency.

In accordance with this invention, a liquid capable of creating vaportension, which affords suificient pressure to drive the fan when thetemperature of cooling water goes up to such a degree that the fanshould be driven, is hermetically filled within the thermo-sensitivechamber 7, and the quantity of the hermetically filled liquid is made aslarge as that required in order to normally maintain both vapor andliquid phases at least until the predetermined pressure (predeterminedtemperature of water) is reached, whereby a pressing state that changesindependently of the variations in the working volume of thethermosensitive chamber but changes according to only variations intemperature can be obtained.

For carrying out this invention, a liquid having desired vapor tensionshould be selected first and then a quantity of the liquid larger thanV.D. value is preferably .fi'lled, wherein V is the maximum workingvolume of the thermo-sensitive chamber and D is the saturated density ofthe vapor of the liquid employed at the temperature (water temperature)in the thermosensitive chamber 7 when the fan starts to be driven.

Materials having effective vapor tension are given in the followingtable by way of example.

DATA BY RAMSAY AND YOUNG Furthermore, in accordance with this invention,the spring is adapted to be actuated by taking out of the chamber thecubical expansive force resulting from expansion of a liquidhermetically filled within the chamber, the liquid which is notvaporized even when the temperature at which the fan should be driven isreached and which has a relatively large expansion coefiicient,including such a material having a relatively high liquifactiontemperature as wax. In this case, wax, or the like may be effectivelyemployed. I

The driving mechanism using temperature setting in accordance with thisinvention will now be described with reference to the embodimentsillustrated in the drawings.

Example 1 (FIG. 1)

The rotor shaft 1, annular plate 18, and clutch 12 were normallycombined with each other in operation, and

during operation of the engine they were normally kept rotating throughthe pulley 22 connected with the shaft 1. The drawing shows a manner inwhich the fan boss is disengaged since the clutch is disconnected.

At the temperature of cooling water of C., the gauge pressure requiredfor driving the fan was 1 kg./cm. the V.D. value of the acetone employedbeing made approximately twice as large as the calculated value. Thevapor tension of the liquid acetone within the thermosensitive chamber 7increased according to the increases in the cooling water temperature,however, the actuation of the working shaft 9 had been restrainedthrough adjustment of the restraining means 11, 11, 11" and 11 until thecooling water temperature reached 77 C., and the said shaft was adaptedto move forward when the temperature would rise beyond 77 C.

An excess of the vapor pressure over the saturated vapor pressureapproximately at 77 C. caused the ball 11 of the restraining means to beextracted from the recess 11 and thus the working shaft 9 moved forwardresisting against the stress of the spring 10, while at the same timethe clutch surfaces 12 and 18 instantly pressed both the inner and outerside surfaces 13" and 13" therebetween. The temperature went up to 80C., very soon, and then the clutch was completely engaged, whereby thefan was rotated at the same speed as that of the rotor shaft. By takinginto consideration that frictional resistance would occur in the innerand outer side surfaces of the boss 13, the iron plates were embedded,thereby the press-contact of the clutch was greatly improved.

Decrease in the vapor tension of the acetone due to decrease in thecooling water temperature resulting from driving the fan caused theinternal pressure within the thermo-sensitive chamber 7 to be decreased,thus reducing the pressing force of the working shaft 9, however, sincethe clutch was pressed into conically engaging relationship with theinner side of the boss by means of the arm 17, the press-contactsurfaces remained resiliently press-contacted between the surfacesengaged into presscontact with each other, whereby the cooling watertemperature gradually decreased while the clutch was engaged.

The time for the clutch remaining resiliently presscontacted to bedisengaged was set so that the clutch would be disengaged when thecooling water temperature became approximately 70 C. (the gauge pressurebecame about 0.6 kg./cm. through adjustment of the resilient force ofthe spring 10 tending to return the spring to its original condition andthe angle of the inner slanting surface of the fan boss. When the clutchwas disengaged, the working shaft 9 was retracted due to the decrease inthe internal pressure within the thermo-sensitive chamber and due to theresilient force of the spring 10 and thus it was returned to theoriginal retaining position and retained thereat.

The above operations were repeated, and the cooling fan was drivenandautomatically controlled.

Example 2 (FIG. 4)

FIG. 4 illustrates another embodiment of this invention, wherein onlythe illustrated part differs from the embodiment shown in FIG. 1 but theremainder thereof is similar to the embodiment shown in FIG. 1. Namely,wax was employed as-the thermo-sensitive material in the embodimentillustrated in FIG. 4, wherein the cubical expansion of the Wax deformedthe spring 10' through the rubber plate 3 and soft rubber 3', therebypressing the working shaft 9. Furthermore, the combination of thereciprocating members 3 and 3', projection 16, and spring 10' shown inFIG. 4 is adapted for performing the same function as the reciprocatingmembers 3 and projection 16 shown in FIG. 1.

What I claim is:

An automatic control apparatus for driving the cooling fan of anautomobile engine comprising, a rotor shaft, a water pump along the axisof said shaft, a working shaft cavity and a thermosensitive cavityformed along said shaft, a reciprocating member connected to said shaftat one end separating said cavities and serving as the Working wall ofsaid thermosensitive cavity, said thermosensitive cavity having acircumferential Wall in contact with water circulated by said pump, saidthermosensitive cavity acting as a confined chamber acting on saidworking wall; thermosensitive material hermetically placed in saidconfined chamber changing the internal pressure in said chamberaccording to temperature variations, longitudinally displacing saidworking wall and reciprocating member, spring means acting on saidreciprocating member biased to maintain said working wall against saidpressure, a clutch arm mounted on said shaft and a clutch with an outerengaging section mounted on the outer end of said clutch arm; atruncated shaped open cone boss including an inner engaging sectiondisposed coaxially with said clutc'h, said clutch being inclined toenter and engage said cone, non-slip resilient means on said engagingsections, and, restraining means for restraining the References Cited bythe Examiner UNITED STATES PATENTS 2,438,161 3/4948 Greenlee 123-41122,658,400 11/1953 Dodge 121341.12 2,879,755 3/1959 Weir 12341.l23,103,308 9/1963 Wolfram 123-4112 OTHER REFERENCES VaporPressure--Temperature Curves, published by Clifford Mfg. Co., Boston,Mass, 1940.

LAURENCE v. EFNER, Primary Examiner.

